The present invention relates to a chip-carrier, and especially relates to a chip-carrier having means for preventing soft error caused by .alpha.-ray, and also the present invention relates to a semiconductor device of chip-carrier type and a semiconductor device having TAB IC, mounted on printed circuit board for preventing soft error caused by .alpha.-ray.
For example, in case of a high degree of integration of a dynamic MOS memory, there are cases where error is not reproduced, which is called soft error and is caused by .alpha.-ray radiated from a very small amount of radioactive material contained in a package.
Conventionally, in order to prevent the information stored in a memory cell of an IC chip from being destroyed by .alpha.-ray radiated from a chip-carrier package, a circuit surface of IC chip was protected by a coating layer of .alpha.-ray shielding resin. In this case, high viscous silicone resins was used as .alpha.-ray shielding resin, and the silicon resin was applied on the circuit surface of an IC chip by potting, prior to packaging of the IC chip in a chip-carrier package. The chip-carrier package is comprised of a chip-carrier substrate provided with bumps to be connected with printed circuit of printed wiring board (not shown), a chip-carrier cover having inverted "U" shape in cross section, which chip-carrier cover is adjoined to the chip-carrier substrate so that a hollow part for accommodating an IC chip is formed. The IC chip is mounted on the chip-carrier substrate face down through lead-formed leads. In order to assemble the chip-carrier by using such a chip-carrier package, first, .alpha.-ray shielding resin is dropped on circuit surface of an IC chip and heat-cured by means of potting equipment. Therefore there are cases where .alpha.-ray shielding silicone resin is protruded into a shape of a mountain to such an extent that the protruded silicone resin makes lead forming difficult. Further when dropped silicone resin on the IC chip is heat-cured, heat is applied to the IC chip, thereby lowering the reliability of the IC chip.